diff --git a/app/genericProcessor/genericProcessor.cpp b/app/genericProcessor/genericProcessor.cpp
index 381c10e4..95591013 100644
--- a/app/genericProcessor/genericProcessor.cpp
+++ b/app/genericProcessor/genericProcessor.cpp
@@ -114,7 +114,6 @@ int main( int argc, char** argv )
 		// set verbose of all stream
 		transcoder.setVerbose( verbose );
 		transcoder.setProcessMethod( avtranscoder::eProcessMethodLongest );
-		//transcoder.setOutputFps( 12 );
 		transcoder.init();
 		
 		if( verbose )
diff --git a/app/presetChecker/presetChecker.cpp b/app/presetChecker/presetChecker.cpp
index e3ca2ac7..d987f3b7 100644
--- a/app/presetChecker/presetChecker.cpp
+++ b/app/presetChecker/presetChecker.cpp
@@ -34,7 +34,7 @@ int main( int argc, char** argv )
 			if( profile.find( avtranscoder::constants::avProfileType )->second == avtranscoder::constants::avProfileTypeAudio )
 			{
 				avtranscoder::AvOutputAudio outputAudio;
-				outputAudio.setProfile( profile, outputAudio.getAudioCodec().getFrameDesc() );
+				outputAudio.setProfile( profile, outputAudio.getAudioCodec().getAudioFrameDesc() );
 			}
 		}
 		catch( ... )
diff --git a/src/AvTranscoder/avTranscoder.i b/src/AvTranscoder/avTranscoder.i
index 5768f912..64ec6df6 100644
--- a/src/AvTranscoder/avTranscoder.i
+++ b/src/AvTranscoder/avTranscoder.i
@@ -40,6 +40,8 @@
 #include <AvTranscoder/essenceStream/IInputEssence.hpp>
 #include <AvTranscoder/essenceStream/AvInputAudio.hpp>
 #include <AvTranscoder/essenceStream/AvInputVideo.hpp>
+#include <AvTranscoder/essenceStream/GeneratorVideo.hpp>
+#include <AvTranscoder/essenceStream/GeneratorAudio.hpp>
 
 #include <AvTranscoder/file/InputFile.hpp>
 #include <AvTranscoder/file/OutputFile.hpp>
@@ -59,6 +61,7 @@ namespace std {
 %template(ChannelVector)   vector< avtranscoder::Channel >;
 %template(ProfileMap)      map< string, string >;
 %template(ProfilesVector)  vector< map< string, string > >;
+%template(DataBuffer)      std::vector< unsigned char >;
 }
 
 %include "AvTranscoder/progress/progress.i"
@@ -90,6 +93,8 @@ namespace std {
 %include <AvTranscoder/essenceStream/IInputEssence.hpp>
 %include <AvTranscoder/essenceStream/AvInputAudio.hpp>
 %include <AvTranscoder/essenceStream/AvInputVideo.hpp>
+%include <AvTranscoder/essenceStream/GeneratorVideo.hpp>
+%include <AvTranscoder/essenceStream/GeneratorAudio.hpp>
 
 %include <AvTranscoder/file/InputFile.hpp>
 %include <AvTranscoder/file/OutputFile.hpp>
diff --git a/src/AvTranscoder/codec/AudioCodec.cpp b/src/AvTranscoder/codec/AudioCodec.cpp
index b96bbdaf..ba94746e 100644
--- a/src/AvTranscoder/codec/AudioCodec.cpp
+++ b/src/AvTranscoder/codec/AudioCodec.cpp
@@ -20,7 +20,7 @@ AudioCodec::AudioCodec( const ICodec& codec )
 {
 }
 
-AudioFrameDesc AudioCodec::getFrameDesc() const
+AudioFrameDesc AudioCodec::getAudioFrameDesc() const
 {
 	assert( _codecContext != NULL );
 	AudioFrameDesc audioFrameDesc;
@@ -33,24 +33,6 @@ AudioFrameDesc AudioCodec::getFrameDesc() const
 	return audioFrameDesc;
 }
 
-const size_t AudioCodec::getSampleRate() const
-{
-	assert( _codecContext != NULL );
-	return _codecContext->sample_rate;
-}
-
-const size_t AudioCodec::getChannels() const
-{
-	assert( _codecContext != NULL );
-	return _codecContext->channels;
-}
-
-const AVSampleFormat AudioCodec::getAVSampleFormat() const
-{
-	assert( _codecContext != NULL );
-	return _codecContext->sample_fmt;
-}
-
 void AudioCodec::setAudioParameters( const AudioFrameDesc& audioFrameDesc )
 {
 	setAudioParameters( audioFrameDesc.getSampleRate(), audioFrameDesc.getChannels(), audioFrameDesc.getAVSampleFormat() );
diff --git a/src/AvTranscoder/codec/AudioCodec.hpp b/src/AvTranscoder/codec/AudioCodec.hpp
index 5d86e1aa..75c0734c 100644
--- a/src/AvTranscoder/codec/AudioCodec.hpp
+++ b/src/AvTranscoder/codec/AudioCodec.hpp
@@ -14,11 +14,8 @@ class AvExport AudioCodec : public ICodec
 	AudioCodec( const ECodecType type, const AVCodecID codecId );
 	AudioCodec( const ICodec& codec );
 
-	AudioFrameDesc getFrameDesc() const;
-	const size_t getSampleRate() const;
-	const size_t getChannels() const;
-	const AVSampleFormat getAVSampleFormat() const;
-	
+	AudioFrameDesc getAudioFrameDesc() const;
+
 	void setAudioParameters( const AudioFrameDesc& audioFrameDesc );
 	void setAudioParameters( const size_t sampleRate, const size_t channels, const AVSampleFormat sampleFormat );
 };
diff --git a/src/AvTranscoder/codec/VideoCodec.cpp b/src/AvTranscoder/codec/VideoCodec.cpp
index faae1076..f29b581b 100644
--- a/src/AvTranscoder/codec/VideoCodec.cpp
+++ b/src/AvTranscoder/codec/VideoCodec.cpp
@@ -23,14 +23,16 @@ VideoCodec::VideoCodec( const ICodec& codec )
 VideoFrameDesc VideoCodec::getVideoFrameDesc() const
 {
 	assert( _codecContext != NULL );
-	VideoFrameDesc VideoFrameDesc;
+
+	VideoFrameDesc videoFrameDesc;
+	videoFrameDesc.setWidth ( _codecContext->width  );
+	videoFrameDesc.setHeight( _codecContext->height );
+	videoFrameDesc.setDar( _codecContext->width, _codecContext->height );
+
 	Pixel pixel( _codecContext->pix_fmt );
+	videoFrameDesc.setPixel( pixel );
 
-	VideoFrameDesc.setWidth ( _codecContext->width  );
-	VideoFrameDesc.setHeight( _codecContext->height );
-	VideoFrameDesc.setPixel ( pixel );
-	VideoFrameDesc.setDar   ( _codecContext->height, _codecContext->width );
-	return VideoFrameDesc;
+	return videoFrameDesc;
 }
 
 std::pair< size_t, size_t > VideoCodec::getTimeBase() const
diff --git a/src/AvTranscoder/codedStream/AvInputStream.cpp b/src/AvTranscoder/codedStream/AvInputStream.cpp
index 3f143b7f..1e6c15e0 100644
--- a/src/AvTranscoder/codedStream/AvInputStream.cpp
+++ b/src/AvTranscoder/codedStream/AvInputStream.cpp
@@ -17,7 +17,6 @@ AvInputStream::AvInputStream( InputFile& inputFile, const size_t streamIndex )
 	: IInputStream( )
 	, _inputFile( &inputFile )
 	, _codec( NULL )
-	, _packetDuration( 0 )
 	, _streamIndex( streamIndex )
 	, _bufferized( false )
 {
@@ -98,7 +97,6 @@ void AvInputStream::addPacket( AVPacket& packet )
 	//std::cout << "add packet for stream " << _streamIndex << std::endl;
 	CodedData data;
 	_streamCache.push_back( data );
-	_packetDuration = packet.duration;
 
 	if( ! _bufferized )
 		return;
@@ -166,11 +164,6 @@ double AvInputStream::getDuration() const
 	return 1.0 * _inputFile->getFormatContext().duration / AV_TIME_BASE;
 }
 
-double AvInputStream::getPacketDuration() const
-{
-	return _packetDuration * av_q2d( _inputFile->getFormatContext().streams[_streamIndex]->time_base );
-}
-
 void AvInputStream::clearBuffering()
 {
 	_streamCache.clear();
diff --git a/src/AvTranscoder/codedStream/AvInputStream.hpp b/src/AvTranscoder/codedStream/AvInputStream.hpp
index e13ebbdf..a34ce6d8 100644
--- a/src/AvTranscoder/codedStream/AvInputStream.hpp
+++ b/src/AvTranscoder/codedStream/AvInputStream.hpp
@@ -30,7 +30,6 @@ class AvExport AvInputStream : public IInputStream
 	AVMediaType getStreamType() const;
 
 	double getDuration() const;
-	double getPacketDuration() const;
 
 	void addPacket( AVPacket& packet );
 
@@ -43,14 +42,13 @@ class AvExport AvInputStream : public IInputStream
 	AVStream* getAVStream() const;
 
 private:
-	InputFile*       _inputFile;
-	std::vector<CodedData> _streamCache;
-
+	InputFile* _inputFile;  ///< Has link (no ownership)
 	ICodec* _codec;  ///< Has ownership
 
-	int              _packetDuration;
-	size_t           _streamIndex;
-	bool             _bufferized;
+	std::vector<CodedData> _streamCache;
+
+	size_t _streamIndex;  ///<  Index of the stream in the input file
+	bool _bufferized;  ///< If the stream is bufferized
 };
 
 }
diff --git a/src/AvTranscoder/codedStream/AvOutputStream.hpp b/src/AvTranscoder/codedStream/AvOutputStream.hpp
index 499c50ba..7d717131 100644
--- a/src/AvTranscoder/codedStream/AvOutputStream.hpp
+++ b/src/AvTranscoder/codedStream/AvOutputStream.hpp
@@ -18,9 +18,9 @@ class AvExport AvOutputStream : public IOutputStream
 	bool wrap( const CodedData& data );
 
 private:
-	OutputFile*      _outputFile;
+	OutputFile* _outputFile;  ///< Has link (no ownership)
 
-	size_t           _streamIndex;
+	size_t _streamIndex;  ///<  Index of the stream in the output file
 };
 
 }
diff --git a/src/AvTranscoder/codedStream/IInputStream.hpp b/src/AvTranscoder/codedStream/IInputStream.hpp
index 1557b0e7..4f9ae9a1 100644
--- a/src/AvTranscoder/codedStream/IInputStream.hpp
+++ b/src/AvTranscoder/codedStream/IInputStream.hpp
@@ -26,7 +26,6 @@ class IInputStream
 	virtual AVMediaType getStreamType() const = 0;
 
 	virtual double getDuration() const = 0;
-	virtual double getPacketDuration() const = 0;
 
 	virtual void setBufferred( const bool bufferized ) = 0;
 
diff --git a/src/AvTranscoder/essenceStream/AvInputAudio.cpp b/src/AvTranscoder/essenceStream/AvInputAudio.cpp
index 0187f20e..e369d88d 100644
--- a/src/AvTranscoder/essenceStream/AvInputAudio.cpp
+++ b/src/AvTranscoder/essenceStream/AvInputAudio.cpp
@@ -20,9 +20,9 @@ namespace avtranscoder
 AvInputAudio::AvInputAudio( AvInputStream& inputStream ) 
 	: IInputEssence()
 	, _inputStream   ( &inputStream )
-	, _codec( eCodecTypeDecoder, inputStream.getAudioCodec().getCodecId() )
+	, _codec( &inputStream.getAudioCodec() )
 	, _frame         ( NULL )
-	, _selectedStream( -1 )
+	, _selectedStream( inputStream.getStreamIndex() )
 {
 }
 
@@ -46,10 +46,10 @@ AvInputAudio::~AvInputAudio()
 
 void AvInputAudio::setup()
 {
-	AVCodecContext* avCodecContext = _codec.getAVCodecContext();
-	AVCodec* avCodec = _codec.getAVCodec();
+	AVCodecContext* avCodecContext = _codec->getAVCodecContext();
+	AVCodec* avCodec = _codec->getAVCodec();
 
-	avCodecContext->channels = _inputStream->getAudioCodec().getChannels();
+	avCodecContext->channels = _inputStream->getAudioCodec().getAudioFrameDesc().getChannels();
 	
 	int ret = avcodec_open2( avCodecContext, avCodec, NULL );
 
@@ -82,10 +82,10 @@ void AvInputAudio::setup()
 
 bool AvInputAudio::readNextFrame( Frame& frameBuffer )
 {
-	if( ! getNextFrame() )
+	if( ! decodeNextFrame() )
 		return false;
 
-	AVCodecContext* avCodecContext = _codec.getAVCodecContext();
+	AVCodecContext* avCodecContext = _codec->getAVCodecContext();
 
 	size_t decodedSize = av_samples_get_buffer_size(
 		NULL, avCodecContext->channels,
@@ -116,14 +116,14 @@ bool AvInputAudio::readNextFrame( Frame& frameBuffer )
 
 bool AvInputAudio::readNextFrame( Frame& frameBuffer, const size_t subStreamIndex )
 {
-	if( ! getNextFrame() )
+	if( ! decodeNextFrame() )
 		return false;
 
 	const int output_nbChannels = 1;
 	const int output_align = 1;
-	size_t decodedSize = av_samples_get_buffer_size(NULL, output_nbChannels, _frame->nb_samples, _codec.getAVCodecContext()->sample_fmt, output_align);
+	size_t decodedSize = av_samples_get_buffer_size(NULL, output_nbChannels, _frame->nb_samples, _codec->getAVCodecContext()->sample_fmt, output_align);
 	
-	size_t nbSubStreams = _codec.getAVCodecContext()->channels;
+	size_t nbSubStreams = _codec->getAVCodecContext()->channels;
 	size_t bytePerSample = av_get_bytes_per_sample( (AVSampleFormat)_frame->format );
 
 	if( subStreamIndex > nbSubStreams - 1 )
@@ -156,7 +156,7 @@ bool AvInputAudio::readNextFrame( Frame& frameBuffer, const size_t subStreamInde
 	return true;
 }
 
-bool AvInputAudio::getNextFrame()
+bool AvInputAudio::decodeNextFrame()
 {
 	int got_frame = 0;
 	while( ! got_frame )
@@ -172,7 +172,7 @@ bool AvInputAudio::getNextFrame()
 		packet.data         = data.getPtr();
 		packet.size         = data.getSize();
 		
-		int ret = avcodec_decode_audio4( _codec.getAVCodecContext(), _frame, &got_frame, &packet );
+		int ret = avcodec_decode_audio4( _codec->getAVCodecContext(), _frame, &got_frame, &packet );
 
 		if( ret < 0 )
 		{
diff --git a/src/AvTranscoder/essenceStream/AvInputAudio.hpp b/src/AvTranscoder/essenceStream/AvInputAudio.hpp
index 394fbf0d..26b0fc9c 100644
--- a/src/AvTranscoder/essenceStream/AvInputAudio.hpp
+++ b/src/AvTranscoder/essenceStream/AvInputAudio.hpp
@@ -23,13 +23,13 @@ class AvExport AvInputAudio : public IInputEssence
 	bool readNextFrame( Frame& frameBuffer, const size_t subStreamIndex );
 
 private:
-	bool getNextFrame();
+	bool decodeNextFrame();
 
-	AvInputStream*     _inputStream;
-	AudioCodec _codec;
-	AVFrame*           _frame;
+	AvInputStream* _inputStream;  ///< Stream from which we read next frames
+	const AudioCodec* _codec;  ///< Audio decoder. Has link (no ownership)
+	AVFrame* _frame;  ///< Libav object to store decoded data
 
-	int                _selectedStream;
+	int _selectedStream;  ///< Index of the selected stream in the input file
 };
 
 }
diff --git a/src/AvTranscoder/essenceStream/AvInputVideo.cpp b/src/AvTranscoder/essenceStream/AvInputVideo.cpp
index 3f39849e..47ac316e 100644
--- a/src/AvTranscoder/essenceStream/AvInputVideo.cpp
+++ b/src/AvTranscoder/essenceStream/AvInputVideo.cpp
@@ -20,9 +20,9 @@ namespace avtranscoder
 AvInputVideo::AvInputVideo( AvInputStream& inputStream )
 	: IInputEssence()
 	, _inputStream   ( &inputStream )
-	, _codec( eCodecTypeDecoder, inputStream.getVideoCodec().getCodecId() )
+	, _codec( &inputStream.getVideoCodec() )
 	, _frame         ( NULL )
-	, _selectedStream( -1 )
+	, _selectedStream( inputStream.getStreamIndex() )
 {
 }
 
@@ -45,8 +45,8 @@ AvInputVideo::~AvInputVideo()
 
 void AvInputVideo::setup()
 {
-	AVCodecContext* avCodecContext = _codec.getAVCodecContext();
-	AVCodec* avCodec = _codec.getAVCodec();
+	AVCodecContext* avCodecContext = _codec->getAVCodecContext();
+	AVCodec* avCodec = _codec->getAVCodec();
 
 	// if( avCodec->capabilities & CODEC_CAP_TRUNCATED )
 	// 	avCodecContext->flags |= CODEC_FLAG_TRUNCATED;
@@ -77,12 +77,36 @@ void AvInputVideo::setup()
 
 bool AvInputVideo::readNextFrame( Frame& frameBuffer )
 {
-	int got_frame = 0;
+	if( ! decodeNextFrame() )
+		return false;
+
+	VideoFrame& imageBuffer = static_cast<VideoFrame&>( frameBuffer );
+
+	size_t decodedSize = avpicture_get_size( (AVPixelFormat)_frame->format, _frame->width, _frame->height );
+	if( ! decodedSize )
+		return false;
+
+	if( imageBuffer.getBuffer().size() != decodedSize )
+		imageBuffer.getBuffer().resize( decodedSize );
+
+	// Copy pixel data from an AVPicture into one contiguous buffer.
+	avpicture_layout( (AVPicture*)_frame, (AVPixelFormat)_frame->format, _frame->width, _frame->height, &imageBuffer.getBuffer()[0], frameBuffer.getBuffer().size() );
+
+	return true;
+}
+
+bool AvInputVideo::readNextFrame( Frame& frameBuffer, const size_t subStreamIndex )
+{
+	return false;
+}
 
+bool AvInputVideo::decodeNextFrame()
+{
+	int got_frame = 0;
 	while( ! got_frame )
 	{
 		CodedData data;
-		if( ! _inputStream->readNextPacket( data ) )
+		if( ! _inputStream->readNextPacket( data ) ) // error or end of file
 			return false;
 
 		AVPacket packet;
@@ -92,7 +116,7 @@ bool AvInputVideo::readNextFrame( Frame& frameBuffer )
 		packet.data         = data.getPtr();
 		packet.size         = data.getSize();
 		
-		int ret = avcodec_decode_video2( _codec.getAVCodecContext(), _frame, &got_frame, &packet );
+		int ret = avcodec_decode_video2( _codec->getAVCodecContext(), _frame, &got_frame, &packet );
 		
 		if( ret < 0 )
 		{
@@ -104,32 +128,17 @@ bool AvInputVideo::readNextFrame( Frame& frameBuffer )
 		
 		av_free_packet( &packet );
 	}
-
-	VideoFrame& imageBuffer = static_cast<VideoFrame&>( frameBuffer );
-
-	size_t decodedSize = avpicture_get_size( (AVPixelFormat)_frame->format, _frame->width, _frame->height );
-	if( imageBuffer.getBuffer().size() != decodedSize )
-		imageBuffer.getBuffer().resize( decodedSize );
-
-	// Copy pixel data from an AVPicture into one contiguous buffer.
-	avpicture_layout( (AVPicture*)_frame, (AVPixelFormat)_frame->format, _frame->width, _frame->height, &imageBuffer.getBuffer()[0], frameBuffer.getBuffer().size() );
-
 	return true;
 }
 
-bool AvInputVideo::readNextFrame( Frame& frameBuffer, const size_t subStreamIndex )
-{
-	return false;
-}
-
 void AvInputVideo::flushDecoder()
 {
-	avcodec_flush_buffers( _codec.getAVCodecContext() );
+	avcodec_flush_buffers( _codec->getAVCodecContext() );
 }
 
 void AvInputVideo::setProfile( const ProfileLoader::Profile& profile )
 {
-	Context codecContext( _codec.getAVCodecContext() );
+	Context codecContext( _codec->getAVCodecContext() );
 
 	for( ProfileLoader::Profile::const_iterator it = profile.begin(); it != profile.end(); ++it )
 	{
diff --git a/src/AvTranscoder/essenceStream/AvInputVideo.hpp b/src/AvTranscoder/essenceStream/AvInputVideo.hpp
index 91fd66bb..8089723f 100644
--- a/src/AvTranscoder/essenceStream/AvInputVideo.hpp
+++ b/src/AvTranscoder/essenceStream/AvInputVideo.hpp
@@ -28,11 +28,13 @@ class AvExport AvInputVideo : public IInputEssence
 	void setProfile( const ProfileLoader::Profile& profile );
 	
 private:
-	AvInputStream*     _inputStream;
-	VideoCodec _codec;
-	AVFrame*           _frame;
+	bool decodeNextFrame();
 
-	int                _selectedStream;
+	AvInputStream* _inputStream;  ///< Stream from which we read next frames
+	const VideoCodec* _codec;  ///< Video decoder. Has link (no ownership)
+	AVFrame* _frame;  ///< Libav object to store decoded data
+
+	int _selectedStream;  ///< Index of the selected stream in the input file
 };
 
 }
diff --git a/src/AvTranscoder/essenceStream/AvOutputVideo.cpp b/src/AvTranscoder/essenceStream/AvOutputVideo.cpp
index 128e3e22..fe082379 100644
--- a/src/AvTranscoder/essenceStream/AvOutputVideo.cpp
+++ b/src/AvTranscoder/essenceStream/AvOutputVideo.cpp
@@ -103,25 +103,7 @@ bool AvOutputVideo::encodeFrame( const Frame& sourceFrame, Frame& codedFrame )
 		memcpy( codedFrame.getPtr(), packet.data, packet.size );
 	}
 #endif
-/*
-		std::string imgType = "";
-		switch( codecContext->coded_frame->pict_type )
-		{
-			case AV_PICTURE_TYPE_NONE : imgType = "None"; break;
-			case AV_PICTURE_TYPE_I : imgType = "I"; break;
-			case AV_PICTURE_TYPE_P : imgType = "P"; break;
-			case AV_PICTURE_TYPE_B : imgType = "B"; break;
-			case AV_PICTURE_TYPE_S : imgType = "S"; break;
-			case AV_PICTURE_TYPE_SI : imgType = "SI"; break;
-			case AV_PICTURE_TYPE_SP : imgType = "SP"; break;
-			case AV_PICTURE_TYPE_BI : imgType = "BI"; break;
-		}
 
-		std::clog << "\tframe " << codecContext->coded_frame->display_picture_number;
-		std::clog << " coded @ " << codecContext->coded_frame->coded_picture_number;
-		std::clog << " type : " << imgType;
-		std::clog << " quality : " << codecContext->coded_frame->quality << std::endl;
-*/
 	av_free_packet( &packet );
 #if LIBAVCODEC_VERSION_MAJOR > 54
 	av_frame_free( &frame );
diff --git a/src/AvTranscoder/essenceStream/GeneratorAudio.cpp b/src/AvTranscoder/essenceStream/GeneratorAudio.cpp
index bd13ef4d..e2a6be2b 100644
--- a/src/AvTranscoder/essenceStream/GeneratorAudio.cpp
+++ b/src/AvTranscoder/essenceStream/GeneratorAudio.cpp
@@ -5,25 +5,15 @@ namespace avtranscoder
 
 GeneratorAudio::GeneratorAudio( )
 	: IInputEssence( )
-	, _codec( NULL )
 	, _inputFrame( NULL )
 	, _frameDesc()
 {
 }
 
-void GeneratorAudio::setAudioCodec( const AudioCodec& codec )
+void GeneratorAudio::setAudioFrameDesc( const AudioFrameDesc& frameDesc )
 {
-	_frameDesc.setFps         ( 25.0 );
-	_codec = &codec;
-
-	_frameDesc.setSampleRate( _codec->getAVCodecContext()->sample_rate );
-	_frameDesc.setChannels( _codec->getAVCodecContext()->channels );
-	_frameDesc.setSampleFormat( _codec->getAVCodecContext()->sample_fmt );
-}
-
-const AudioCodec& GeneratorAudio::getAudioCodec()
-{
-	return *_codec;
+	_frameDesc = frameDesc;
+	_frameDesc.setFps( 25. );
 }
 
 void GeneratorAudio::setFrame( Frame& inputFrame )
diff --git a/src/AvTranscoder/essenceStream/GeneratorAudio.hpp b/src/AvTranscoder/essenceStream/GeneratorAudio.hpp
index 0c8e80d1..2f14c946 100644
--- a/src/AvTranscoder/essenceStream/GeneratorAudio.hpp
+++ b/src/AvTranscoder/essenceStream/GeneratorAudio.hpp
@@ -12,9 +12,8 @@ class AvExport GeneratorAudio : public IInputEssence
 public:
 	GeneratorAudio( );
 
-	void setAudioCodec( const AudioCodec& codec );
-
-	const AudioCodec& getAudioCodec();
+	AudioFrameDesc& getAudioFrameDesc() { return _frameDesc; }
+	void setAudioFrameDesc( const AudioFrameDesc& frameDesc );
 	
 	void setup() {}
 	
@@ -24,8 +23,7 @@ class AvExport GeneratorAudio : public IInputEssence
 	bool readNextFrame( Frame& frameBuffer, const size_t subStreamIndex );
 
 private:
-	const AudioCodec* _codec;
-	Frame*         _inputFrame;
+	Frame* _inputFrame;  ///< Has link (no ownership)
 	AudioFrameDesc _frameDesc;
 };
 
diff --git a/src/AvTranscoder/essenceStream/GeneratorVideo.cpp b/src/AvTranscoder/essenceStream/GeneratorVideo.cpp
index e1a37861..30e8ed3e 100644
--- a/src/AvTranscoder/essenceStream/GeneratorVideo.cpp
+++ b/src/AvTranscoder/essenceStream/GeneratorVideo.cpp
@@ -7,22 +7,14 @@ namespace avtranscoder
 
 GeneratorVideo::GeneratorVideo( )
 	: IInputEssence( )
-	, _codec( NULL )
 	, _inputFrame( NULL )
-	, _videoFrameDesc()
-	, _numberOfView( 1 )
+	, _frameDesc()
 {
 }
 
-void GeneratorVideo::setVideoCodec( const VideoCodec& codec )
+void GeneratorVideo::setVideoFrameDesc( const VideoFrameDesc& frameDesc )
 {
-	_codec = &codec;
-	_videoFrameDesc = _codec->getVideoFrameDesc();
-}
-
-const VideoCodec& GeneratorVideo::getVideoCodec()
-{
-	return *_codec;
+	_frameDesc = frameDesc;
 }
 
 void GeneratorVideo::setFrame( Frame& inputFrame )
@@ -32,30 +24,32 @@ void GeneratorVideo::setFrame( Frame& inputFrame )
 
 bool GeneratorVideo::readNextFrame( Frame& frameBuffer )
 {
+	// Generate black image
 	if( ! _inputFrame )
 	{
 		// @todo support PAL (0 to 255) and NTFS (16 to 235)
 		int fillChar = 0;
 
-		if( frameBuffer.getSize() != _videoFrameDesc.getDataSize() )
-			frameBuffer.getBuffer().resize( _videoFrameDesc.getDataSize() );
+		if( frameBuffer.getSize() != _frameDesc.getDataSize() )
+			frameBuffer.getBuffer().resize( _frameDesc.getDataSize() );
 
-		VideoFrameDesc desc( _codec->getVideoFrameDesc() );
+		VideoFrameDesc desc( _frameDesc );
 		Pixel rgbPixel;
 		rgbPixel.setColorComponents( eComponentRgb );
 		rgbPixel.setPlanar( false );
 		desc.setPixel( rgbPixel );
 
 		VideoFrame intermediateBuffer( desc );
-		intermediateBuffer.getBuffer().resize( _videoFrameDesc.getDataSize() );
-		memset( intermediateBuffer.getPtr(), fillChar, _videoFrameDesc.getDataSize() );
+		intermediateBuffer.getBuffer().resize( _frameDesc.getDataSize() );
+		memset( intermediateBuffer.getPtr(), fillChar, _frameDesc.getDataSize() );
 
 		VideoTransform videoEssenceTransform;
 		videoEssenceTransform.convert( intermediateBuffer, frameBuffer );
 
 		return true;
 	}
-	
+
+	// Take image from _inputFrame
 	if( frameBuffer.getSize() != _inputFrame->getSize() )
 		frameBuffer.getBuffer().resize( _inputFrame->getSize() );
 	std::memcpy( frameBuffer.getPtr(), _inputFrame->getPtr(), _inputFrame->getSize() );
diff --git a/src/AvTranscoder/essenceStream/GeneratorVideo.hpp b/src/AvTranscoder/essenceStream/GeneratorVideo.hpp
index 54a206ab..f32513bf 100644
--- a/src/AvTranscoder/essenceStream/GeneratorVideo.hpp
+++ b/src/AvTranscoder/essenceStream/GeneratorVideo.hpp
@@ -12,10 +12,8 @@ class AvExport GeneratorVideo : public IInputEssence
 public:
 	GeneratorVideo( );
 
-	// Stream properties
-	void setVideoCodec( const VideoCodec& codec );
-
-	const VideoCodec& getVideoCodec();
+	VideoFrameDesc& getVideoFrameDesc() { return _frameDesc; }
+	void setVideoFrameDesc( const VideoFrameDesc& frameDesc );
 	
 	void setup() {}
 
@@ -25,11 +23,8 @@ class AvExport GeneratorVideo : public IInputEssence
 	bool readNextFrame( Frame& frameBuffer, const size_t subStreamIndex );
 
 private:
-	const VideoCodec* _codec;
-	Frame* _inputFrame;
-	VideoFrameDesc _videoFrameDesc;
-
-	size_t         _numberOfView;
+	Frame* _inputFrame;  ///< Has link (no ownership)
+	VideoFrameDesc _frameDesc;
 };
 
 }
diff --git a/src/AvTranscoder/essenceStream/IInputEssence.hpp b/src/AvTranscoder/essenceStream/IInputEssence.hpp
index 33f7968a..8e232dc0 100644
--- a/src/AvTranscoder/essenceStream/IInputEssence.hpp
+++ b/src/AvTranscoder/essenceStream/IInputEssence.hpp
@@ -31,6 +31,13 @@ class AvExport IInputEssence
 	 * @return status of decoding
 	 */
 	virtual bool readNextFrame( Frame& frameBuffer, const size_t subStreamIndex ) = 0;
+
+	/**
+	 * Set the next frame of the input stream
+	 * @note Not yet implemented for AvInputVideo and AvInputAudio
+	 * @param inputFrame: the new next frame
+	 */
+	virtual void setFrame( Frame& inputFrame ) {}
 };
 
 }
diff --git a/src/AvTranscoder/frame/VideoFrame.hpp b/src/AvTranscoder/frame/VideoFrame.hpp
index 169dc3ee..4423d41f 100644
--- a/src/AvTranscoder/frame/VideoFrame.hpp
+++ b/src/AvTranscoder/frame/VideoFrame.hpp
@@ -40,7 +40,7 @@ class AvExport VideoFrameDesc
 	
 	void setWidth ( const size_t width     ) { _width = width; }
 	void setHeight( const size_t height    ) { _height = height; }
-	void setPixel ( const Pixel  pixel     ) { _pixel = pixel; }
+	void setPixel( const Pixel&  pixel ) { _pixel = pixel; }
 	void setDar( const size_t num, const size_t den ) { _displayAspectRatio.num = num; _displayAspectRatio.den = den; }
 	void setDar( const Rational ratio ) { _displayAspectRatio = ratio; }
 	
diff --git a/src/AvTranscoder/option/Context.hpp b/src/AvTranscoder/option/Context.hpp
index b804943c..b7e43e8d 100644
--- a/src/AvTranscoder/option/Context.hpp
+++ b/src/AvTranscoder/option/Context.hpp
@@ -11,6 +11,9 @@
 namespace avtranscoder
 {
 
+typedef std::vector<Option> OptionArray;
+typedef std::map<std::string, Option> OptionMap;
+
 /**
  * @brief Wrapper of AVContext.
  * Can access Options through the corresponding context.
@@ -37,8 +40,8 @@ class AvExport Context
 		loadOptions( avContext, req_flags );
 	}
 
-	std::vector<Option> getOptions();
-	std::map<std::string, Option>& getOptionsMap() { return _options; }
+	OptionArray getOptions();
+	OptionMap& getOptionsMap() { return _options; }
 
 	Option& getOption( const std::string& optionName ) { return _options.at(optionName); }
 
@@ -46,7 +49,7 @@ class AvExport Context
 	void loadOptions( void* av_class, int req_flags );
 
 private:
-	std::map<std::string, Option> _options;
+	OptionMap _options;
 	void* _avContext;  ///< Has link (no ownership)
 };
 
diff --git a/src/AvTranscoder/option/Option.cpp b/src/AvTranscoder/option/Option.cpp
index 16aeeafb..eccceb3c 100644
--- a/src/AvTranscoder/option/Option.cpp
+++ b/src/AvTranscoder/option/Option.cpp
@@ -88,7 +88,7 @@ std::string Option::getDefaultString() const
 
 std::pair<int, int> Option::getDefaultRatio() const
 {
-	return std::pair<int, int>( _avOption->default_val.q.num, _avOption->default_val.q.den );
+	return std::make_pair( _avOption->default_val.q.num, _avOption->default_val.q.den );
 }
 //av_make_error_string
 void Option::setFlag( const std::string& flag, const bool enable )
diff --git a/src/AvTranscoder/transcoder/StreamTranscoder.cpp b/src/AvTranscoder/transcoder/StreamTranscoder.cpp
index 35455665..c8b236fb 100644
--- a/src/AvTranscoder/transcoder/StreamTranscoder.cpp
+++ b/src/AvTranscoder/transcoder/StreamTranscoder.cpp
@@ -112,7 +112,7 @@ StreamTranscoder::StreamTranscoder(
 			_transform = new VideoTransform();
 
 			GeneratorVideo* generatorVideo = new GeneratorVideo();
-			generatorVideo->setVideoCodec( outputVideo->getVideoCodec() );
+			generatorVideo->setVideoFrameDesc( outputVideo->getVideoCodec().getVideoFrameDesc() );
 			_generatorEssence = generatorVideo;
 			
 			break;
@@ -126,7 +126,7 @@ StreamTranscoder::StreamTranscoder(
 
 			_outputEssence = outputAudio;
 			
-			AudioFrameDesc outputFrameDesc( _inputStream->getAudioCodec().getFrameDesc() );
+			AudioFrameDesc outputFrameDesc( _inputStream->getAudioCodec().getAudioFrameDesc() );
 			outputFrameDesc.setParameters( profile );
 			if( subStreamIndex > -1 )
 			{
@@ -137,17 +137,17 @@ StreamTranscoder::StreamTranscoder(
 
 			_outputStream = &outputFile.addAudioStream( outputAudio->getAudioCodec() );
 
-			AudioFrameDesc inputFrameDesc( _inputStream->getAudioCodec().getFrameDesc() );
+			AudioFrameDesc inputFrameDesc( _inputStream->getAudioCodec().getAudioFrameDesc() );
 			if( subStreamIndex > -1 )
 				inputFrameDesc.setChannels( 1 );
 			
 			_sourceBuffer = new AudioFrame( inputFrameDesc );
-			_frameBuffer  = new AudioFrame( outputAudio->getAudioCodec().getFrameDesc() );
+			_frameBuffer  = new AudioFrame( outputAudio->getAudioCodec().getAudioFrameDesc() );
 			
 			_transform = new AudioTransform();
 
 			GeneratorAudio* generatorAudio = new GeneratorAudio();
-			generatorAudio->setAudioCodec( outputAudio->getAudioCodec() );
+			generatorAudio->setAudioFrameDesc( outputAudio->getAudioCodec().getAudioFrameDesc() );
 			_generatorEssence = generatorAudio;
 
 			break;
@@ -162,7 +162,7 @@ StreamTranscoder::StreamTranscoder(
 }
 
 StreamTranscoder::StreamTranscoder(
-		const ICodec& inputCodec,
+		IInputEssence& inputEssence,
 		OutputFile& outputFile,
 		const ProfileLoader::Profile& profile
 	)
@@ -170,7 +170,7 @@ StreamTranscoder::StreamTranscoder(
 	, _outputStream( NULL )
 	, _sourceBuffer( NULL )
 	, _frameBuffer( NULL )
-	, _inputEssence( NULL )
+	, _inputEssence( &inputEssence )
 	, _generatorEssence( NULL )
 	, _currentEssence( NULL )
 	, _outputEssence( NULL )
@@ -189,14 +189,8 @@ StreamTranscoder::StreamTranscoder(
 
 	if( profile.find( constants::avProfileType )->second == constants::avProfileTypeVideo )
 	{
-		// Create input essence based on a given input VideoCodec
-		GeneratorVideo* generatorVideo = new GeneratorVideo();
-		const VideoCodec& inputVideoCodec = static_cast<const VideoCodec&>( inputCodec );
-		generatorVideo->setVideoCodec( inputVideoCodec );
-		_inputEssence = generatorVideo;
-
 		// Create inputFrame, and outputFrame which is based on a given profile
-		VideoFrameDesc inputFrameDesc = inputVideoCodec.getVideoFrameDesc();
+		VideoFrameDesc inputFrameDesc = static_cast<GeneratorVideo&>( inputEssence ).getVideoFrameDesc();
 		VideoFrameDesc outputFrameDesc = inputFrameDesc;
 		outputFrameDesc.setParameters( profile );
 		_sourceBuffer = new VideoFrame( inputFrameDesc );
@@ -216,14 +210,8 @@ StreamTranscoder::StreamTranscoder(
 	}
 	else if( profile.find( constants::avProfileType )->second == constants::avProfileTypeAudio )
 	{
-		// Create input essence based on a given input AudioCodec
-		GeneratorAudio* generatorAudio = new GeneratorAudio();
-		const AudioCodec& inputAudioCodec = static_cast<const AudioCodec&>( inputCodec );
-		generatorAudio->setAudioCodec( inputAudioCodec );
-		_inputEssence = generatorAudio;
-
 		// Create inputFrame, and outputFrame which is based on a given profile
-		AudioFrameDesc inputFrameDesc = inputAudioCodec.getFrameDesc();
+		AudioFrameDesc inputFrameDesc = static_cast<GeneratorAudio&>( inputEssence ).getAudioFrameDesc();
 		AudioFrameDesc outputFrameDesc = inputFrameDesc;
 		outputFrameDesc.setParameters( profile );
 		_sourceBuffer = new AudioFrame( inputFrameDesc );
@@ -251,10 +239,12 @@ StreamTranscoder::~StreamTranscoder()
 {
 	delete _frameBuffer;
 	delete _sourceBuffer;
+	// _inputEssence is a link to an existing InputEssence if _generatorEssence is NULL
+	if( _generatorEssence )
+		delete _inputEssence;
 	delete _generatorEssence;
 	delete _outputEssence;
 	delete _transform;
-	delete _inputEssence;
 }
 
 void StreamTranscoder::init()
@@ -332,10 +322,10 @@ bool StreamTranscoder::processTranscode()
 	if( _currentEssence->readNextFrame( *_sourceBuffer ) )
 	{
 		if( _verbose )
-			std::cout << "convert " << _sourceBuffer->getSize() << std::endl;
+			std::cout << "convert (" << _sourceBuffer->getSize() << " bytes)" << std::endl;
 		_transform->convert( *_sourceBuffer, *_frameBuffer );
 		if( _verbose )
-			std::cout << "encode " << _frameBuffer->getSize() << std::endl;
+			std::cout << "encode (" << _frameBuffer->getSize() << " bytes)" << std::endl;
 		_outputEssence->encodeFrame( *_frameBuffer, data );
 	}
 	else
@@ -354,7 +344,7 @@ bool StreamTranscoder::processTranscode()
 	}
 
 	if( _verbose )
-		std::cout << "wrap (" << data.getSize() << ")" << std::endl;
+		std::cout << "wrap (" << data.getSize() << " bytes)" << std::endl;
 	_outputStream->wrap( data );
 	return true;
 }
@@ -384,10 +374,10 @@ bool StreamTranscoder::processTranscode( const int subStreamIndex )
 	if( _currentEssence->readNextFrame( *_sourceBuffer, subStreamIndex ) )
 	{
 		if( _verbose )
-			std::cout << "convert " << std::endl;
+			std::cout << "convert (" << _sourceBuffer->getSize() << " bytes)" << std::endl;
 		_transform->convert( *_sourceBuffer, *_frameBuffer );
 		if( _verbose )
-			std::cout << "encode" << std::endl;
+			std::cout << "encode (" << _frameBuffer->getSize() << " bytes)" << std::endl;
 		_outputEssence->encodeFrame( *_frameBuffer, data );
 	}
 	else
@@ -405,7 +395,7 @@ bool StreamTranscoder::processTranscode( const int subStreamIndex )
 		}
 	}
 	if( _verbose )
-		std::cout << "wrap (" << data.getSize() << ")" << std::endl;
+		std::cout << "wrap (" << data.getSize() << " bytes)" << std::endl;
 	_outputStream->wrap( data );
 	return true;
 }
diff --git a/src/AvTranscoder/transcoder/StreamTranscoder.hpp b/src/AvTranscoder/transcoder/StreamTranscoder.hpp
index a8ef25c3..40ea7271 100644
--- a/src/AvTranscoder/transcoder/StreamTranscoder.hpp
+++ b/src/AvTranscoder/transcoder/StreamTranscoder.hpp
@@ -36,7 +36,7 @@ class AvExport StreamTranscoder
 	 * @brief encode from a generated stream
 	 * @note offset feature has no sense here
 	 **/
-	StreamTranscoder( const ICodec& inputCodec, OutputFile& outputFile, const ProfileLoader::Profile& profile );
+	StreamTranscoder( IInputEssence& inputEssence, OutputFile& outputFile, const ProfileLoader::Profile& profile );
 
 	~StreamTranscoder();
 
@@ -57,18 +57,23 @@ class AvExport StreamTranscoder
 	void switchToGeneratorEssence();
 	void switchToInputEssence();
 
-	void setVerbose( bool verbose = true ){ _verbose = verbose; }
-
-	void setInfinityStream( bool isInfinity ) { _infinityStream = isInfinity; }
-
-	void setOffset( bool offset = true ){ _offset = offset; }
-
 	/**
 	 * @brief Get the duration of the stream.
 	 * @note if it's a generated stream, return limit of double.
 	 */
 	double getDuration() const;
 
+	/**
+	 * @return a reference to the current essence processed in this stream.
+	 */
+	IInputEssence& getCurrentEssence() const { return *_currentEssence; }
+
+	void setVerbose( bool verbose = true ){ _verbose = verbose; }
+
+	void setInfinityStream( bool isInfinity ) { _infinityStream = isInfinity; }
+
+	void setOffset( bool offset = true ){ _offset = offset; }
+
 private:
 	bool processRewrap();
 	bool processTranscode();
@@ -88,28 +93,15 @@ class AvExport StreamTranscoder
 
 	ITransform* _transform;
 
-	int  _subStreamIndex;
-
-	/**
-	 * @brief How many frame processed for this StreamTranscoder.
-	 */
-	size_t _frameProcessed;
-	/**
-	 * @brief Offset, in frame, at the beginning of the StreamTranscoder.
-	 */
-	size_t _offset;
+	int  _subStreamIndex;  ///< Index of channel that is processed from the input stream (-1 if no demultiplexing).
 
-	bool _takeFromGenerator;
+	size_t _frameProcessed;  ///< How many frame processed for this StreamTranscoder.
+	size_t _offset;  ///< Offset, in frame, at the beginning of the StreamTranscoder.
 
+	bool _takeFromGenerator;  ///< Is the data processed are taken from a generator.
 	bool _verbose;
-
-	bool _offsetPassed;
-
-	/**
-	 * @brief Automatic switch to a generator
-	 * @note not applicable when rewrap
-	 */
-	bool _infinityStream;
+	bool _offsetPassed;  ///< Is the offset at the beginning of the stream is finished.
+	bool _infinityStream;  ///< Automatically switch to a generator at the end of the stream (not applicable when rewrap);
 };
 
 }
diff --git a/src/AvTranscoder/transcoder/Transcoder.cpp b/src/AvTranscoder/transcoder/Transcoder.cpp
index 2ee022a6..fa53e826 100644
--- a/src/AvTranscoder/transcoder/Transcoder.cpp
+++ b/src/AvTranscoder/transcoder/Transcoder.cpp
@@ -1,5 +1,8 @@
 #include "Transcoder.hpp"
 
+#include <AvTranscoder/essenceStream/GeneratorAudio.hpp>
+#include <AvTranscoder/essenceStream/GeneratorVideo.hpp>
+
 #include <AvTranscoder/progress/NoDisplayProgress.hpp>
 
 #include <limits>
@@ -14,8 +17,8 @@ Transcoder::Transcoder( OutputFile& outputFile )
 	: _outputFile( outputFile )
 	, _inputFiles()
 	, _streamTranscoders()
+	, _streamTranscodersAllocated()
 	, _profileLoader( true )
-	, _outputFps( 25 )
 	, _eProcessMethod ( eProcessMethodLongest )
 	, _mainStreamIndex( 0 )
 	, _verbose( false )
@@ -29,7 +32,11 @@ Transcoder::~Transcoder()
 	{
 		delete (*it);
 	}
-	for( std::vector< StreamTranscoder* >::iterator it = _streamTranscoders.begin(); it != _streamTranscoders.end(); ++it )
+	for( std::vector< StreamTranscoder* >::iterator it = _streamTranscodersAllocated.begin(); it != _streamTranscodersAllocated.end(); ++it )
+	{
+		delete (*it);
+	}
+	for( std::vector< IInputEssence* >::iterator it = _internalEssences.begin(); it != _internalEssences.end(); ++it )
 	{
 		delete (*it);
 	}
@@ -89,8 +96,8 @@ void Transcoder::add( const std::string& filename, const size_t streamIndex, Pro
 		throw std::runtime_error( "Can't transcode a stream without filename indicated" );
 
 	if( _verbose )
-		std::cout << "Add transcoded stream" << std::endl;
-	addTranscodeStream( filename, streamIndex, profile, offset );
+		std::cout << "add transcoding stream" << std::endl;
+	addTranscodeStream( filename, streamIndex, -1, profile, offset );
 }
 
 void Transcoder::add( const std::string& filename, const size_t streamIndex, ProfileLoader::Profile& profile, ICodec& codec, const size_t offset )
@@ -110,7 +117,7 @@ void Transcoder::add( const std::string& filename, const size_t streamIndex, Pro
 	{
 		if( _verbose )
 			std::cout << "Add transcoded stream" << std::endl;
-		addTranscodeStream( filename, streamIndex, profile, offset );
+		addTranscodeStream( filename, streamIndex, -1, profile, offset );
 	}
 }
 
@@ -313,7 +320,7 @@ void Transcoder::process( IProgress& progress )
 		if( ! processFrame() )
 			break;
 		
-		if( progress.progress( 1 / _outputFps * ( frame ), totalDuration ) == eJobStatusCancel )
+		if( progress.progress( 1 / 25. * ( frame ), totalDuration ) == eJobStatusCancel )
 		{
 			break;
 		}
@@ -374,7 +381,9 @@ void Transcoder::setVerbose( bool verbose )
 void Transcoder::addRewrapStream( const std::string& filename, const size_t streamIndex )
 {
 	InputFile* referenceFile = addInputFile( filename, streamIndex );
-	_streamTranscoders.push_back( new StreamTranscoder( referenceFile->getStream( streamIndex ), _outputFile ) );
+
+	_streamTranscodersAllocated.push_back( new StreamTranscoder( referenceFile->getStream( streamIndex ), _outputFile ) );
+	_streamTranscoders.push_back( _streamTranscodersAllocated.back() );
 }
 
 void Transcoder::addTranscodeStream( const std::string& filename, const size_t streamIndex, const size_t subStreamIndex, const size_t offset )
@@ -405,29 +414,8 @@ void Transcoder::addTranscodeStream( const std::string& filename, const size_t s
 		case AVMEDIA_TYPE_VIDEO:
 		case AVMEDIA_TYPE_AUDIO:
 		{
-			_streamTranscoders.push_back( new StreamTranscoder( referenceFile->getStream( streamIndex ), _outputFile, profile, subStreamIndex , offset ) );
-			break;
-		}
-		case AVMEDIA_TYPE_DATA:
-		case AVMEDIA_TYPE_SUBTITLE:
-		case AVMEDIA_TYPE_ATTACHMENT:
-		default:
-		{
-			throw std::runtime_error( "unsupported media type in transcode setup" );
-		}
-	}
-}
-
-void Transcoder::addTranscodeStream( const std::string& filename, const size_t streamIndex, ProfileLoader::Profile& profile, const size_t offset )
-{
-	InputFile* referenceFile = addInputFile( filename, streamIndex );
-
-	switch( referenceFile->getStreamType( streamIndex ) )
-	{
-		case AVMEDIA_TYPE_VIDEO:
-		case AVMEDIA_TYPE_AUDIO:
-		{
-			_streamTranscoders.push_back( new StreamTranscoder( referenceFile->getStream( streamIndex ), _outputFile, profile, -1 , offset ) );
+			_streamTranscodersAllocated.push_back( new StreamTranscoder( referenceFile->getStream( streamIndex ), _outputFile, profile, subStreamIndex , offset ) );
+			_streamTranscoders.push_back( _streamTranscodersAllocated.back() );
 			break;
 		}
 		case AVMEDIA_TYPE_DATA:
@@ -449,7 +437,8 @@ void Transcoder::addTranscodeStream( const std::string& filename, const size_t s
 		case AVMEDIA_TYPE_VIDEO:
 		case AVMEDIA_TYPE_AUDIO:
 		{
-			_streamTranscoders.push_back( new StreamTranscoder( referenceFile->getStream( streamIndex ), _outputFile, profile, subStreamIndex, offset ) );
+			_streamTranscodersAllocated.push_back( new StreamTranscoder( referenceFile->getStream( streamIndex ), _outputFile, profile, subStreamIndex, offset ) );
+			_streamTranscoders.push_back( _streamTranscodersAllocated.back() );
 			break;
 		}
 		case AVMEDIA_TYPE_DATA:
@@ -467,20 +456,29 @@ void Transcoder::addDummyStream( const ProfileLoader::Profile& profile, const IC
 	if( ! profile.count( constants::avProfileType ) )
 		throw std::runtime_error( "unable to found stream type (audio, video, etc.)" );
 
-	if( profile.find( constants::avProfileType )->second == constants::avProfileTypeAudio )
+	if( profile.find( constants::avProfileType )->second == constants::avProfileTypeVideo )
 	{
 		if( _verbose )
-			std::cout << "add a generated audio stream" << std::endl;
+			std::cout << "add a generated video stream" << std::endl;
 
-		_streamTranscoders.push_back( new StreamTranscoder( codec, _outputFile, profile ) );
-	}
+		GeneratorVideo* video = new GeneratorVideo();
+		video->setVideoFrameDesc( static_cast<const VideoCodec&>( codec ).getVideoFrameDesc() );
+		_internalEssences.push_back( video );
 
-	if( profile.find( constants::avProfileType )->second == constants::avProfileTypeVideo )
+		_streamTranscodersAllocated.push_back( new StreamTranscoder( *video, _outputFile, profile ) );
+		_streamTranscoders.push_back( _streamTranscodersAllocated.back() );
+	}
+	else if( profile.find( constants::avProfileType )->second == constants::avProfileTypeAudio )
 	{
 		if( _verbose )
-			std::cout << "add generated video stream" << std::endl;
+			std::cout << "add a generated audio stream" << std::endl;
+
+		GeneratorAudio* audio = new GeneratorAudio();
+		audio->setAudioFrameDesc( static_cast<const AudioCodec&>( codec ).getAudioFrameDesc() );
+		_internalEssences.push_back( audio );
 
-		_streamTranscoders.push_back( new StreamTranscoder( codec, _outputFile, profile ) );
+		_streamTranscodersAllocated.push_back( new StreamTranscoder( *audio, _outputFile, profile ) );
+		_streamTranscoders.push_back( _streamTranscodersAllocated.back() );
 	}
 }
 
diff --git a/src/AvTranscoder/transcoder/Transcoder.hpp b/src/AvTranscoder/transcoder/Transcoder.hpp
index 4f22c6fe..1b852e1e 100644
--- a/src/AvTranscoder/transcoder/Transcoder.hpp
+++ b/src/AvTranscoder/transcoder/Transcoder.hpp
@@ -6,10 +6,8 @@
 #include <AvTranscoder/file/InputFile.hpp>
 #include <AvTranscoder/file/OutputFile.hpp>
 
-#include <AvTranscoder/codedStream/IInputStream.hpp>
-
-#include <AvTranscoder/essenceStream/GeneratorAudio.hpp>
-#include <AvTranscoder/essenceStream/GeneratorVideo.hpp>
+#include <AvTranscoder/essenceStream/IInputEssence.hpp>
+#include <AvTranscoder/essenceStream/IOutputEssence.hpp>
 
 #include <AvTranscoder/ProfileLoader.hpp>
 
@@ -94,9 +92,8 @@ class AvExport Transcoder
 
 	/**
 	 * @brief Add the stream
-	 * @note The stream will be deleted in Transcoder's destructor.
 	 */
-	void add( StreamTranscoder& stream );
+	void add( StreamTranscoder& streamTranscoder);
 
 	/**
 	 * @brief Initialize all streams added, by ensure process necessary frames in case of latency.
@@ -117,6 +114,12 @@ class AvExport Transcoder
 	 */
 	void process( IProgress& progress );
 
+	/**
+	 * @param streamIndex: careful about the order of stream insertion of the Transcoder.
+	 * @return a reference to a stream manage by the Transcoder.
+	 */
+	StreamTranscoder& getStreamTranscoder( size_t streamIndex ) const { return *_streamTranscoders.at( streamIndex ); }
+
 	/**
 	 * @brief Set the transcodage politic.
 	 * @note Call it after adding the streams.
@@ -131,23 +134,10 @@ class AvExport Transcoder
 	 */
 	void setVerbose( bool verbose = true );
 
-	/**
-	 * @brief Set FPS of output media file.
-	 * @note By default 25 frames per second.
-     */
-	void setOutputFps( double fps ) { _outputFps = fps; }
-
 private:
-
 	void addRewrapStream( const std::string& filename, const size_t streamIndex );
 
-        /**
-         * @note Get profile from input
-         */
-        void addTranscodeStream( const std::string& filename, const size_t streamIndex, const size_t subStreamIndex, const size_t offset );
-
-	void addTranscodeStream( const std::string& filename, const size_t streamIndex, ProfileLoader::Profile& profile, const size_t offset = 0 );
-
+	void addTranscodeStream( const std::string& filename, const size_t streamIndex, const size_t subStreamIndex, const size_t offset );  ///< Get profile from input
 	void addTranscodeStream( const std::string& filename, const size_t streamIndex, const size_t subStreamIndex, ProfileLoader::Profile& profile, const size_t offset = 0 );
 
 	void addDummyStream( const ProfileLoader::Profile& profile, const ICodec& codec );
@@ -175,11 +165,12 @@ class AvExport Transcoder
 	OutputFile&                      _outputFile;  ///< The output media file after process.
 	std::vector< InputFile* >        _inputFiles;  ///< The list of input files which contain added streams.
 
-	std::vector< StreamTranscoder* > _streamTranscoders;  ///< The streams of the output media file after process.
+	std::vector< StreamTranscoder* > _streamTranscoders;  ///< All streams of the output media file after process.
+	std::vector< StreamTranscoder* > _streamTranscodersAllocated;  ///< Streams allocated inside the Transcoder.
 
-	ProfileLoader _profileLoader;  ///< Objet to get existing profiles, and add new ones for the Transcoder.
+	std::vector< IInputEssence* > _internalEssences;  ///< Internal essences allocated inside the Transcoder.
 
-	double _outputFps;
+	ProfileLoader _profileLoader;  ///< Manage existing profiles, and add new ones for the Transcoder.
 
 	EProcessMethod _eProcessMethod;
 
diff --git a/src/AvTranscoder/transform/VideoTransform.cpp b/src/AvTranscoder/transform/VideoTransform.cpp
index 437c4590..5d097652 100644
--- a/src/AvTranscoder/transform/VideoTransform.cpp
+++ b/src/AvTranscoder/transform/VideoTransform.cpp
@@ -40,11 +40,6 @@ bool VideoTransform::init( const Frame& srcFrame, const Frame& dstFrame )
 	const VideoFrame& src = static_cast<const VideoFrame&>( srcFrame );
 	const VideoFrame& dst = static_cast<const VideoFrame&>( dstFrame );
 
-	assert( src.desc().getWidth()  != 0 );
-	assert( src.desc().getHeight() != 0 );
-	assert( src.desc().getWidth()  == dst.desc().getWidth()  );
-	assert( src.desc().getHeight() == dst.desc().getHeight() );
-
 	_imageConvertContext = sws_getContext(
 		src.desc().getWidth(), src.desc().getHeight(), src.desc().getPixelDesc().findPixel(),
 		dst.desc().getWidth(), dst.desc().getHeight(), dst.desc().getPixelDesc().findPixel(),
diff --git a/src/AvTranscoder/util.cpp b/src/AvTranscoder/util.cpp
index c5ddcdc7..fa3584d1 100644
--- a/src/AvTranscoder/util.cpp
+++ b/src/AvTranscoder/util.cpp
@@ -41,7 +41,6 @@ std::vector<std::string> getPixelFormats( const std::string& videoCodecName )
 	else
 	{
 		const AVCodec* videoCodec = avcodec_find_encoder_by_name( videoCodecName.c_str() );
-
 		if( videoCodec && videoCodec->pix_fmts != NULL )
 		{
 			size_t pix_fmt = 0;
@@ -52,7 +51,7 @@ std::vector<std::string> getPixelFormats( const std::string& videoCodecName )
 #else
 				const AVPixFmtDescriptor* pix_desc = av_pix_fmt_desc_get( videoCodec->pix_fmts[pix_fmt] );
 #endif
-				if( ! pix_desc->name )
+				if( ! pix_desc || ! pix_desc->name )
 					continue;
 				pixelFormats.push_back( std::string( pix_desc->name ) );
 				++pix_fmt;
@@ -66,6 +65,7 @@ std::vector<std::string> getSampleFormats( const std::string& audioCodecName )
 {
 	std::vector<std::string> sampleFormats;
 	
+	// all audio codec concerned
 	if( audioCodecName.empty() )
 	{
 		for( size_t sampleFormat = 0; sampleFormat < AV_SAMPLE_FMT_NB; ++sampleFormat)
@@ -73,6 +73,7 @@ std::vector<std::string> getSampleFormats( const std::string& audioCodecName )
 			sampleFormats.push_back( av_get_sample_fmt_name( static_cast<AVSampleFormat>( sampleFormat ) ) );
 		}
 	}
+	// specific audio codec
 	else
 	{
 		const AVCodec* audioCodec = avcodec_find_encoder_by_name( audioCodecName.c_str() );
@@ -109,7 +110,7 @@ std::vector<std::string> getFormatsLongNames()
 	AVOutputFormat* fmt = NULL;
 	while( ( fmt = av_oformat_next( fmt ) ) )
 	{
-		// add only format with video track
+		// skip undefined codec
 		if( fmt->video_codec == AV_CODEC_ID_NONE )
 			continue;
 
@@ -127,7 +128,7 @@ std::vector<std::string> getFormatsShortNames()
 	AVOutputFormat* fmt = NULL;
 	while( ( fmt = av_oformat_next( fmt ) ) )
 	{
-		// add only format with video track
+		// skip undefined codec
 		if( fmt->video_codec == AV_CODEC_ID_NONE )
 			continue;
 
@@ -261,7 +262,7 @@ std::vector<std::string> getAudioCodecsShortNames()
 	return audioCodecsShortNames;
 }
 
-std::map< std::string, std::vector<Option> > getOutputFormatOptions()
+OptionArrayMap getOutputFormatOptions()
 {
 	av_register_all();
 
@@ -288,7 +289,7 @@ std::map< std::string, std::vector<Option> > getOutputFormatOptions()
 	return optionsPerFormat;
 }
 
-std::map< std::string, std::vector<Option> > getVideoCodecOptions()
+OptionArrayMap getVideoCodecOptions()
 {
 	std::map< std::string, std::vector<Option> > videoCodecOptions;
 	
@@ -319,7 +320,7 @@ std::map< std::string, std::vector<Option> > getVideoCodecOptions()
 	return videoCodecOptions;
 }
 
-std::map< std::string, std::vector<Option> > getAudioCodecOptions()
+OptionArrayMap getAudioCodecOptions()
 {
 	std::map< std::string, std::vector<Option> > audioCodecOptions;
 	
diff --git a/src/AvTranscoder/util.hpp b/src/AvTranscoder/util.hpp
index 02173bde..100af79b 100644
--- a/src/AvTranscoder/util.hpp
+++ b/src/AvTranscoder/util.hpp
@@ -3,6 +3,8 @@
 
 #include "common.hpp"
 
+#include <AvTranscoder/option/Context.hpp>
+
 extern "C" {
 #include <libavutil/pixfmt.h>
 #include <libavutil/samplefmt.h>
@@ -15,7 +17,7 @@ extern "C" {
 namespace avtranscoder
 {
 
-class Option;
+typedef std::map<std::string, OptionArray> OptionArrayMap;
 
 /**
 *  @brief Get pixel format supported by a video codec.
@@ -65,17 +67,17 @@ std::vector<std::string> getAudioCodecsShortNames();
 /**
  * @brief Get the list of options for each output format
  */
-std::map< std::string, std::vector<Option> > getOutputFormatOptions();
+OptionArrayMap getOutputFormatOptions();
 
 /**
  * @brief Get the list of options for each video codec
  */
-std::map< std::string, std::vector<Option> > getVideoCodecOptions();
+OptionArrayMap getVideoCodecOptions();
 
 /**
  * @brief Get the list of options for each audio codec
  */
-std::map< std::string, std::vector<Option> > getAudioCodecOptions();
+OptionArrayMap getAudioCodecOptions();
 
 }
 
diff --git a/test/pyTest/testProperties.py b/test/pyTest/testProperties.py
index 8a380f04..0e23acc1 100644
--- a/test/pyTest/testProperties.py
+++ b/test/pyTest/testProperties.py
@@ -54,3 +54,4 @@ def testAddImpossibleMetadata():
 	properties = inputFile.getProperties()
 
 	assert_not_in( metadata_to_check, properties.metadatas )
+
diff --git a/test/pyTest/testSetFrame.py b/test/pyTest/testSetFrame.py
new file mode 100644
index 00000000..225f7ce8
--- /dev/null
+++ b/test/pyTest/testSetFrame.py
@@ -0,0 +1,118 @@
+import os
+
+from nose.tools import *
+
+from pyAvTranscoder import avtranscoder as av
+
+
+def testSetVideoFrame():
+	"""
+	Generate a video stream, and set its frame during process.
+	"""
+	profileLoader = av.ProfileLoader(True)
+
+	# create output
+	outputFileName = "testSetVideoFrame.mov"
+	ouputFile = av.OutputFile( outputFileName )
+
+	# create video frame and codec
+	imageDesc = av.VideoFrameDesc()
+	imageDesc.setWidth( 1920 )
+	imageDesc.setHeight( 1080 )
+	imageDesc.setDar( 1920, 1080 )
+
+	inputPixel = av.Pixel()
+	inputPixel.setColorComponents( av.eComponentRgb );
+	inputPixel.setPlanar( False );
+
+	imageDesc.setPixel( inputPixel );
+
+	video = av.GeneratorVideo()
+	video.setVideoFrameDesc( imageDesc )
+
+	# create transcoder and add a video stream
+	transcoder = av.Transcoder( ouputFile )
+	streamTranscoder = av.StreamTranscoder( video, ouputFile, profileLoader.getProfile( "xdcamhd422" ) )
+	transcoder.add( streamTranscoder )
+
+	# start process
+	transcoder.init()
+	ouputFile.beginWrap()
+
+	# process 255 frames
+	for i in range(0,255):
+		transcoder.processFrame()
+		# set video frame
+		frame = av.VideoFrame( imageDesc )
+		frame.getBuffer().assign(frame.getBuffer().size(), i)
+		video.setFrame( frame )
+
+	# end process
+	ouputFile.endWrap()
+
+	# get dst file of transcode
+	dst_inputFile = av.InputFile( outputFileName )
+	progress = av.NoDisplayProgress()
+	dst_inputFile.analyse( progress, av.InputFile.eAnalyseLevelFast )
+	dst_properties = dst_inputFile.getProperties()
+	dst_videoStream = dst_properties.videoStreams[0]
+
+	assert_equals( "mpeg2video", dst_videoStream.codecName )
+	assert_equals( "MPEG-2 video", dst_videoStream.codecLongName )
+	assert_equals( 1920, dst_videoStream.width )
+	assert_equals( 1080, dst_videoStream.height )
+	assert_equals( 16, dst_videoStream.dar.num )
+	assert_equals( 9, dst_videoStream.dar.den )
+
+def testSetAudioFrame():
+	"""
+	Generate a audio stream, and set its frame during process.
+	"""
+	profileLoader = av.ProfileLoader(True)
+
+	# create output
+	outputFileName = "testSetAudioFrame.wav"
+	ouputFile = av.OutputFile( outputFileName )
+
+	# create video frame and codec
+	audioDesc = av.AudioFrameDesc()
+	audioDesc.setSampleRate( 48000 )
+	audioDesc.setChannels( 1 )
+	audioDesc.setSampleFormat( "s32" )
+
+	audio = av.GeneratorAudio()
+	audio.setAudioFrameDesc( audioDesc )
+
+	# create transcoder and add a video stream
+	transcoder = av.Transcoder( ouputFile )
+	streamTranscoder = av.StreamTranscoder( audio, ouputFile, profileLoader.getProfile( "wave24b48kmono" ) )
+	transcoder.add(  streamTranscoder )
+
+	# start process
+	transcoder.init()
+	ouputFile.beginWrap()
+
+	# process 255 frames
+	for i in range(0,255):
+		transcoder.processFrame()
+		# set video frame
+		frame = av.AudioFrame( audioDesc )
+		frame.getBuffer().assign(frame.getBuffer().size(), i)
+		audio.setFrame( frame )
+
+	# end process
+	ouputFile.endWrap()
+
+	# get dst file of transcode
+	dst_inputFile = av.InputFile( outputFileName )
+	progress = av.NoDisplayProgress()
+	dst_inputFile.analyse( progress, av.InputFile.eAnalyseLevelFast )
+	dst_properties = dst_inputFile.getProperties()
+	dst_audioStream = dst_properties.audioStreams[0]
+
+	assert_equals( "pcm_s24le", dst_audioStream.codecName )
+	assert_equals( "PCM signed 24-bit little-endian", dst_audioStream.codecLongName )
+	assert_equals( "signed 32 bits", dst_audioStream.sampleFormat )
+	assert_equals( 48000, dst_audioStream.sampleRate )
+	assert_equals( 1, dst_audioStream.channels )
+
diff --git a/test/pyTest/testTranscoderAdd.py b/test/pyTest/testTranscoderAdd.py
new file mode 100644
index 00000000..ea5a6f91
--- /dev/null
+++ b/test/pyTest/testTranscoderAdd.py
@@ -0,0 +1,30 @@
+import os
+
+from nose.tools import *
+
+from pyAvTranscoder import avtranscoder as av
+
+
+def testAddStreamTranscoder():
+	"""
+	Add a streamTranscoder to the Transcoder, and process rewrap of an audio stream.
+	"""
+	# input
+	inputFile = av.InputFile( os.environ['AVTRANSCODER_TEST_AUDIO_FILE'] )
+	inputIndex = 0
+	inputStream = inputFile.getStream( inputIndex )
+	inputStream.setBufferred( True )
+
+	# output
+	outputFileName = "testAddStreamTranscoder.avi"
+	ouputFile = av.OutputFile( outputFileName )
+
+	streamTranscoder = av.StreamTranscoder( inputStream, ouputFile )
+	transcoder = av.Transcoder( ouputFile )
+	transcoder.add( streamTranscoder)
+
+	# process
+	progress = av.NoDisplayProgress()
+	transcoder.init()
+	transcoder.process( progress )
+
diff --git a/test/pyTest/testTranscoderDummy.py b/test/pyTest/testTranscoderDummy.py
index 1dd7624b..cdc145f4 100644
--- a/test/pyTest/testTranscoderDummy.py
+++ b/test/pyTest/testTranscoderDummy.py
@@ -121,3 +121,4 @@ def testTranscodeDummyVideo():
 	ouputFile.beginWrap()
 	transcoder.processFrame()
 	ouputFile.endWrap()
+
diff --git a/test/pyTest/testTranscoderRewrap.py b/test/pyTest/testTranscoderRewrap.py
index c904e4b9..2ab24659 100644
--- a/test/pyTest/testTranscoderRewrap.py
+++ b/test/pyTest/testTranscoderRewrap.py
@@ -168,3 +168,4 @@ def testRewrapVideoStream():
 		dst_metadata = dst_videoStream.metadatas[metadata]
 
 		assert_equals( src_metadata, dst_metadata )
+
diff --git a/test/pyTest/testTranscoderTranscode.py b/test/pyTest/testTranscoderTranscode.py
index c025f7e4..b069614c 100644
--- a/test/pyTest/testTranscoderTranscode.py
+++ b/test/pyTest/testTranscoderTranscode.py
@@ -225,3 +225,4 @@ def testTranscodeWave16b48kmono():
 
 # 	assert_equals( "mpeg2video", dst_videoStream.codecName )
 # 	assert_equals( "yuv420p", dst_videoStream.pixelName )
+